diff --git a/lib/ai/providers/volcano-vision.ts b/lib/ai/providers/volcano-vision.ts
index 4ec5d2cba..0e4447594 100644
--- a/lib/ai/providers/volcano-vision.ts
+++ b/lib/ai/providers/volcano-vision.ts
@@ -8,6 +8,8 @@ interface VolcanoVisionConfig {
   baseURL: string;
 }
 
+type VolcanoImageSizeBucket = "1K" | "2K" | "4K";
+
 type VolcanoUrlRewriteConfig = {
   publicOrigin: string;
   endpointBase: string;
@@ -20,7 +22,43 @@ const VOLCANO_INLINE_MAX_SIDE = 1024;
 const DEFAULT_VOLCANO_IMAGE_SIZE = "2K";
 const SEEDREAM_MODEL_ID_PATTERN = /doubao-seedream-4-5/i;
 
-function normalizeVolcanoImageSize(imageSize?: string): "1K" | "2K" | "4K" {
+const VOLCANO_ASPECT_SIZE_OPTIONS: Record<
+  VolcanoImageSizeBucket,
+  Array<{ width: number; height: number }>
+> = {
+  "1K": [
+    { width: 1024, height: 1024 },
+    { width: 1152, height: 864 },
+    { width: 864, height: 1152 },
+    { width: 1280, height: 720 },
+    { width: 720, height: 1280 },
+    { width: 1248, height: 832 },
+    { width: 832, height: 1248 },
+    { width: 1512, height: 648 },
+  ],
+  "2K": [
+    { width: 2048, height: 2048 },
+    { width: 2304, height: 1728 },
+    { width: 1728, height: 2304 },
+    { width: 2560, height: 1440 },
+    { width: 1440, height: 2560 },
+    { width: 2496, height: 1664 },
+    { width: 1664, height: 2496 },
+    { width: 3024, height: 1296 },
+  ],
+  "4K": [
+    { width: 4096, height: 4096 },
+    { width: 4704, height: 3520 },
+    { width: 3520, height: 4704 },
+    { width: 5504, height: 3040 },
+    { width: 3040, height: 5504 },
+    { width: 4992, height: 3328 },
+    { width: 3328, height: 4992 },
+    { width: 6240, height: 2656 },
+  ],
+};
+
+function normalizeVolcanoImageSize(imageSize?: string): VolcanoImageSizeBucket {
   const normalized = String(imageSize || "").trim().toUpperCase();
   if (normalized === "1K" || normalized === "2K" || normalized === "4K") {
     return normalized;
@@ -31,8 +69,11 @@ function normalizeVolcanoImageSize(imageSize?: string): "1K" | "2K" | "4K" {
 function resolveVolcanoImageSizeForModel(
   modelId: string,
   imageSize?: string
-): "1K" | "2K" | "4K" {
-  const normalized = normalizeVolcanoImageSize(imageSize);
+): VolcanoImageSizeBucket {
+  const exactSize = normalizeVolcanoExactSize(imageSize);
+  const normalized = exactSize
+    ? inferVolcanoImageSizeBucketFromExactSize(exactSize)
+    : normalizeVolcanoImageSize(imageSize);
   if (SEEDREAM_MODEL_ID_PATTERN.test(modelId)) {
     // doubao-seedream-4-5 在当前链路下 1K 会返回 InvalidParameter，强制回落到 2K
     if (normalized === "1K") {
@@ -45,6 +86,165 @@ function resolveVolcanoImageSizeForModel(
   return normalized;
 }
 
+function inferVolcanoImageSizeBucketFromExactSize(exactSize: string): VolcanoImageSizeBucket {
+  const [widthRaw, heightRaw] = exactSize.split("x");
+  const width = Number(widthRaw);
+  const height = Number(heightRaw);
+  const area = width * height;
+  if (area >= 7_000_000) return "4K";
+  if (area >= 2_000_000) return "2K";
+  return "1K";
+}
+
+function normalizeVolcanoExactSize(imageSize?: string): string | null {
+  const normalized = String(imageSize || "")
+    .trim()
+    .toLowerCase()
+    .replace(/[×*]/g, "x");
+  const match = normalized.match(/^(\d{2,5})x(\d{2,5})$/);
+  if (!match) return null;
+
+  const width = Number(match[1]);
+  const height = Number(match[2]);
+  if (!Number.isFinite(width) || !Number.isFinite(height) || width <= 0 || height <= 0) {
+    return null;
+  }
+
+  return `${width}x${height}`;
+}
+
+function parseVolcanoAspectRatio(aspectRatio?: string): number | null {
+  const normalized = String(aspectRatio || "").trim().toLowerCase();
+  if (!normalized || normalized === "auto") return null;
+
+  const match = normalized.match(/^(\d+(?:\.\d+)?)\s*:\s*(\d+(?:\.\d+)?)$/);
+  if (!match) return null;
+
+  const width = Number(match[1]);
+  const height = Number(match[2]);
+  if (!Number.isFinite(width) || !Number.isFinite(height) || width <= 0 || height <= 0) {
+    return null;
+  }
+
+  return width / height;
+}
+
+function resolveVolcanoAspectAwareSize(
+  aspectRatio: string | undefined,
+  imageSize: VolcanoImageSizeBucket
+): string | null {
+  const targetRatio = parseVolcanoAspectRatio(aspectRatio);
+  if (!targetRatio) return null;
+
+  const candidates = VOLCANO_ASPECT_SIZE_OPTIONS[imageSize];
+  const best = candidates.reduce((currentBest, option) => {
+    const currentDelta = Math.abs(currentBest.width / currentBest.height - targetRatio);
+    const optionDelta = Math.abs(option.width / option.height - targetRatio);
+    if (optionDelta < currentDelta) {
+      return option;
+    }
+    if (optionDelta === currentDelta) {
+      return option.width * option.height > currentBest.width * currentBest.height
+        ? option
+        : currentBest;
+    }
+    return currentBest;
+  }, candidates[0]);
+
+  return `${best.width}x${best.height}`;
+}
+
+function getFirstImageSource(image: string | string[] | undefined): string | null {
+  if (!image) return null;
+  if (Array.isArray(image)) {
+    return image.find((item) => typeof item === "string" && item.length > 0) || null;
+  }
+  return typeof image === "string" && image.length > 0 ? image : null;
+}
+
+async function inferImageAspectRatioFromSource(
+  image: string | string[] | undefined
+): Promise<string | null> {
+  const source = getFirstImageSource(image);
+  if (!source) return null;
+
+  try {
+    let buffer: Buffer | null = null;
+
+    if (source.startsWith("data:image")) {
+      const match = source.match(/^data:[^;]+;base64,(.+)$/);
+      if (match?.[1]) {
+        buffer = Buffer.from(match[1], "base64");
+      }
+    } else if (/^https?:\/\//i.test(source)) {
+      const controller = new AbortController();
+      const timeoutId = setTimeout(() => controller.abort(), VOLCANO_IMAGE_FETCH_TIMEOUT_MS);
+      try {
+        const response = await fetch(source, { signal: controller.signal });
+        if (!response.ok) {
+          console.warn("[Volcano Vision] Failed to fetch reference image for aspect inference:", response.status);
+          return null;
+        }
+        buffer = Buffer.from(await response.arrayBuffer());
+      } finally {
+        clearTimeout(timeoutId);
+      }
+    }
+
+    if (!buffer || buffer.length === 0) return null;
+
+    const sharp = await import("sharp");
+    const metadata = await sharp.default(buffer).metadata();
+    if (!metadata.width || !metadata.height) return null;
+
+    return `${metadata.width}:${metadata.height}`;
+  } catch (error) {
+    console.warn("[Volcano Vision] Failed to infer reference aspect ratio:", error);
+    return null;
+  }
+}
+
+async function resolveVolcanoRequestSize(params: {
+  modelId: string;
+  imageSize?: string;
+  aspectRatio?: string;
+  image?: string | string[];
+}): Promise<{
+  size: string;
+  fallbackSize: VolcanoImageSizeBucket;
+  inferredAspectRatio: string | null;
+}> {
+  const fallbackSize = resolveVolcanoImageSizeForModel(params.modelId, params.imageSize);
+  const explicitSize = normalizeVolcanoExactSize(params.imageSize);
+  if (explicitSize) {
+    return { size: explicitSize, fallbackSize, inferredAspectRatio: null };
+  }
+
+  const requestedAspectRatio = String(params.aspectRatio || "").trim();
+  const inferredAspectRatio =
+    requestedAspectRatio === "auto" && params.image
+      ? await inferImageAspectRatioFromSource(params.image)
+      : null;
+  const resolvedAspectRatio = inferredAspectRatio || requestedAspectRatio;
+  const aspectAwareSize = resolveVolcanoAspectAwareSize(resolvedAspectRatio, fallbackSize);
+
+  if (inferredAspectRatio) {
+    console.log(`[Volcano Vision] Inferred reference aspect ratio: ${inferredAspectRatio}`);
+  }
+
+  if (aspectAwareSize) {
+    console.log(
+      `[Volcano Vision] Resolved size: aspectRatio=${resolvedAspectRatio}, imageSize=${fallbackSize} => ${aspectAwareSize}`
+    );
+    return { size: aspectAwareSize, fallbackSize, inferredAspectRatio };
+  }
+
+  console.log(
+    `[Volcano Vision] Resolved size: aspectRatio=${resolvedAspectRatio || "default"}, imageSize=${fallbackSize} => ${fallbackSize}`
+  );
+  return { size: fallbackSize, fallbackSize, inferredAspectRatio };
+}
+
 function guessImageMimeTypeFromUrl(url: string): string {
   const cleanUrl = url.split("?")[0]?.toLowerCase() || "";
   if (cleanUrl.endsWith(".png")) return "image/png";
@@ -61,6 +261,11 @@ function shouldRetryVolcanoWithInlineImage(errorText: string): boolean {
   );
 }
 
+function shouldRetryVolcanoWithBucketSize(errorText: string): boolean {
+  if (!errorText) return false;
+  return /invalidparameter|invalid parameter|size|resolution|dimension/i.test(errorText);
+}
+
 async function fetchImageAsDataUri(url: string): Promise<string | null> {
   if (!/^https?:\/\//i.test(url)) return null;
 
@@ -358,7 +563,7 @@ function formatImageResponse(
 
   // 🆕 统一使用 ||| 分隔符格式（与 Gemini 保持一致）
   // 格式: ![thumb|||原图URL|||尺寸](缩略图URL)
-  const normalizedSize = normalizeVolcanoImageSize(imageSize);
+  const normalizedSize = normalizeVolcanoExactSize(imageSize) || normalizeVolcanoImageSize(imageSize);
   return images
     .map((img) => `![thumb|||${img.original}|||${normalizedSize}](${img.thumbnail})`)
     .join("\n\n");
@@ -460,7 +665,8 @@ async function sendVolcanoRequest(
   messages: any[],
   modelId: string,
   maxImages: number = 3, // 默认 3 张，故障转移时传 1
-  imageSize: string = DEFAULT_VOLCANO_IMAGE_SIZE
+  imageSize: string = DEFAULT_VOLCANO_IMAGE_SIZE,
+  aspectRatio?: string
 ): Promise<VolcanoVisionResponse> {
   const url = `${baseURL}/api/v3/images/generations`;
   
@@ -496,11 +702,16 @@ async function sendVolcanoRequest(
   console.log("[Volcano Vision] Image count:", image ? (Array.isArray(image) ? image.length : 1) : 0);
   
   // 构建请求体
-  const normalizedSize = resolveVolcanoImageSizeForModel(modelId, imageSize);
+  const resolvedSize = await resolveVolcanoRequestSize({
+    modelId,
+    imageSize,
+    aspectRatio,
+    image,
+  });
   const requestBody: any = {
     model: modelId,
     prompt,
-    size: normalizedSize,
+    size: resolvedSize.size,
     watermark: false,
     response_format: "url",
     stream: false,
@@ -591,16 +802,37 @@ async function sendVolcanoRequest(
     }
 
     const errorBody = (error as any)?.body || String(error || "");
-    if (requestBody.image && shouldRetryVolcanoWithInlineImage(errorBody)) {
+    let inlineRetryBody = requestBody;
+    let latestError: unknown = error;
+    let latestErrorBody = errorBody;
+
+    if (
+      requestBody.size !== resolvedSize.fallbackSize &&
+      shouldRetryVolcanoWithBucketSize(errorBody)
+    ) {
+      console.warn(
+        `[Volcano Vision] Retrying with bucket size fallback: ${requestBody.size} -> ${resolvedSize.fallbackSize}`
+      );
+      const sizeFallbackBody = { ...requestBody, size: resolvedSize.fallbackSize };
+      try {
+        return await executeRequest(sizeFallbackBody, "size-fallback");
+      } catch (sizeError) {
+        latestError = sizeError;
+        latestErrorBody = (sizeError as any)?.body || String(sizeError || "");
+        inlineRetryBody = sizeFallbackBody;
+      }
+    }
+
+    if (inlineRetryBody.image && shouldRetryVolcanoWithInlineImage(latestErrorBody)) {
       console.warn("[Volcano Vision] Retrying with inline base64 image payload...");
-      const inlineImage = await convertImageFieldToInlineDataUri(requestBody.image);
+      const inlineImage = await convertImageFieldToInlineDataUri(inlineRetryBody.image);
       if (inlineImage) {
-        const retryBody = { ...requestBody, image: inlineImage };
+        const retryBody = { ...inlineRetryBody, image: inlineImage };
         return await executeRequest(retryBody, "inline-retry");
       }
       console.warn("[Volcano Vision] Inline retry skipped: failed to convert source image(s).");
     }
-    throw error;
+    throw latestError;
   }
 }
 
@@ -612,7 +844,8 @@ async function* sendVolcanoStreamRequest(
   apiKey: string,
   messages: any[],
   modelId: string,
-  imageSize: string = DEFAULT_VOLCANO_IMAGE_SIZE
+  imageSize: string = DEFAULT_VOLCANO_IMAGE_SIZE,
+  aspectRatio?: string
 ): AsyncGenerator<VolcanoVisionStreamEvent> {
   const url = `${baseURL}/api/v3/images/generations`;
   
@@ -626,11 +859,16 @@ async function* sendVolcanoStreamRequest(
   console.log("[Volcano Vision] Image count:", image ? (Array.isArray(image) ? image.length : 1) : 0);
   
   // 构建请求体
-  const normalizedSize = normalizeVolcanoImageSize(imageSize);
+  const resolvedSize = await resolveVolcanoRequestSize({
+    modelId,
+    imageSize,
+    aspectRatio,
+    image,
+  });
   const requestBody: any = {
     model: modelId,
     prompt,
-    size: normalizedSize,
+    size: resolvedSize.size,
     watermark: false,
     response_format: "url",
     stream: true,
@@ -747,12 +985,14 @@ export function createVolcanoVision({ apiKey, baseURL }: VolcanoVisionConfig) {
             options.messages,
             activeModelId,
             maxImages,
-            imageSize
+            imageSize,
+            options.imageParams?.aspectRatio
           );
           
           // 提取图片并上传到 S3
           const imageUrls = await extractAndUploadImages(response);
-          const markdownText = formatImageResponse(imageUrls, imageSize);
+          const responseImageSize = response.data?.find((item) => item.size)?.size || imageSize;
+          const markdownText = formatImageResponse(imageUrls, responseImageSize);
 
           console.log(
             `[Volcano Vision] Generated ${imageUrls.length} images (uploaded to S3)`
@@ -797,7 +1037,14 @@ export function createVolcanoVision({ apiKey, baseURL }: VolcanoVisionConfig) {
             modelId,
             options.imageParams?.imageSize
           );
-          for await (const event of sendVolcanoStreamRequest(baseURL, apiKey, options.messages, modelId, imageSize)) {
+          for await (const event of sendVolcanoStreamRequest(
+            baseURL,
+            apiKey,
+            options.messages,
+            modelId,
+            imageSize,
+            options.imageParams?.aspectRatio
+          )) {
             if (event.type === "image_generation.partial_succeeded" && event.url) {
               // 每张图片生成完成后立即上传并发送
               try {